1. Field of the Invention
This invention relates to a method of making a sheet-form article from fibre-reinforced resin matrix composite material comprising the steps of arranging the fibres and uncured resin in tooling which defines a more or less flat moulding face corresponding to the shape which it is desired that a face of the article should assume, covering the fibres and resin with a gas-tight membrane, reducing the gas pressure around the fibres and resin between the tooling and the membrane, and curing the resin at elevated temperature.
2. Description of Related Art
Conventionally such articles are moulded over-size in the aforementioned tooling, the moulded articles being edge-trimmed to size subsequent to the moulding stage.
It has always been considered that the difficulties of allowing for thermal expansion exclude any possibility of moulding "net-to-size". There has, in addition, been a feeling that the mechanical properties of the moulded composite material may be relatively poor around the edge of the moulding, compared with the bulk properties away from the edge of the moulding. Trimming subsequent to moulding cuts away this suspect material.
The trimming of mouldings after they have been cured is, however, an expensive process and can introduce unwelcome delamination on the trimmed edge. It is usually necessary to coat the trimmed edge, and this represents another unwelcome expense.